Final answer:
Scarring occurs when the skin repairs damage but fails to regenerate the original skin structure. Scar tissue is collagen-rich and lacks the normal cellular structure of skin, preventing the regeneration of accessory structures like hair follicles and sweat glands.
Step-by-step explanation:
Scarring occurs in cases where there is repair of skin damage, but the skin fails to regenerate the original skin structure. Fibroblasts generate scar tissue in the form of collagen, resulting in the formation of a scar. The tissue in a scar is fibrous in nature and does not allow for the regeneration of accessory structures such as hair follicles, sweat glands, or sebaceous glands. Instead, the scar tissue is collagen-rich and lacks the typical cellular structure of normal skin.